Hairbrush



FIG. 1 is a side elevation of the hairbrush of my design and the opposite side is identical thereto;

FIG. 2 is a top plan view thereof and the bottom plan view is identical thereto;

FIG. 3 is a left end view thereof; and

FIG. 4 is a right end view thereof. 

The ornamental design for a hairbrush, as shown and described. 